Cell Biology

• Cell Theory


  • All living things are made up of one or more cells
  • Cells are the structural & functional units of all living things
  • All cells come from preexisting cells through cell division
• Cell


  Smallest unit capable of performing life functions (e.g. digestion, respiration, excretion, reproduction)
• Why are Cells so Small?

  • Surface Area to Volume Ratio
  • Increasing Relative Surface Area

  
• Two Types of Cells

  • Prokaryotic
  • Eukaryotic
• Prokaryotic Cells


  • Do not have structures surrounded by membranes
  • Few internal structures
  • One-celled organisms, Bacteria & Archaea
• Eukaryotic Cells


  • Contain organelles surrounded by membranes
  • Animals, Plants, Fungi, "Protists"
• Cell Membrane


  • Outer membrane of cell that controls movement in and out of the cell
  • Double layer
• Cell Wall


  • Most commonly found in plant cells & bacteria
  • Supports & protects cells
• Nucleus


  • Directs cell activities
  • Separated from cytoplasm by nuclear membrane
  • Contains genetic material - DNA
• Nuclear Membrane


  • Surrounds nucleus
  • Made of two layers
  • Openings allow material to enter and leave nucleus
• Chromosomes


  • In nucleus
  • Made of DNA
  • Contain instructions for traits & characteristics
• Nucleolus


  • Inside nucleus
  • Contains rRNA to build ribosomes
• Cytosol


  • Gel-like mixture (fluid component of cytoplasm)
  • Surrounded by cell membrane
• Endoplasmic Reticulum


  • Moves materials around in cell
  • Smooth type: lacks ribosomes, lipid synthesis
  • Rough type: ribosomes embedded in surface, protein synthesis
• Ribosomes


  • Each cell contains thousands
  • Make proteins
  • Found on ribosomes & floating throughout the cell
• Golgi Bodies


  • Protein 'packaging plant'
  • Move materials within the cell
  • Move materials out of the cell
• Lysosome


  • Digestive 'plant' for proteins, fats, and carbohydrates
  • Transports undigested material to cell membrane for removal
  • Cell breaks down if lysosome explodes
• Vacuoles


  • Membrane-bound sacs for storage, digestion, and waste removal
  • Contains water solution
  • Help plants maintain shape
• Mitochondria


  • Produces energy through chemical reactions – breaking down fats & carbohydrates
  • Controls level of water and other materials in cell
  • Recycles and decomposes proteins, fats, and carbohydrates
• Chloroplast


  • Usually found in plant cells
  • Contains green chlorophyll
  • Where photosynthesis takes place
• Centrioles


  • Every animal-like cell has two small organelles
  • Help the cell when it comes time to divide
  • Put to work in both the process of mitosis and the process of meiosis